06.12.11

Heart Disease Poses Surprising Threat to New Moms

Pregnancy-related deaths are on the rise in the U.S., and a new report reveals that heart disease is a major factor. By Jennifer Block.

A few days after Michelle MacDonald gave birth, she felt alarmingly short of breath—like someone was holding her head under water, then yanking it up every few seconds for her to steal a few gasps of air. But when the first-time mother complained from her hospital bed, the postpartum nurses in Fredericton, New Brunswick, were unconcerned.

"Everyone just kind of brushed it off," she told The Daily Beast. "I think they thought I had new-mom anxiety."

Two days passed before she was seen by a cardiologist who instantly recognized her symptoms as red flags: MacDonald was showing all the signs of peripartum cardiomyopathy, a little-known yet highly lethal form of cardiac disease, in which the heart muscle thins and weakens late in pregnancy and following childbirth. Terrified, she was finally rushed to intensive care.

If MacDonald hadn't been persistent in demanding treatment, the otherwise healthy 31-year-old's outcome would likely have been fatal. According to a new report out of California, the number of maternal deaths in the state has doubled in recent years, mirroring a disturbing trend nationwide: the U.S. now has the highest maternal mortality rate of any industrialized nation. (Women in Canada face a 1 in 5,600 risk of maternal death, while women in the U.S. face a 1 in 2,100 risk.) But the investigation uncovered something else: the largest proportion of pregnancy-related deaths, about one in five, appears to be caused by heart disease, including cardiomyopathy.

A maternal death is like a shuttle disaster. There are multiple points of failure at multiple points in time throughout multiple places in the system.

The study's authors were surprised by the numbers. After all, until last December, the Centers for Disease Control didn't even identify cardiovascular disease as a major cause of maternal death. Investigators say it rose to No. 1 in California because they went beyond the CDC's traditional surveillance of death certificates and reviewed the medical records of all women who died within a year of giving birth.

"We searched this huge database in order to identify women who died of pregnancy-related causes but who weren't captured in the original statistics," said researcher Christine Morton. They discovered that almost half of the women who had died of cardiomyopathy weren't counted—probably because the women had died months after giving birth, not within the six weeks traditionally allowed for a "maternal death."

Heart disease isn't typically on the minds of obstetricians and midwives. At prenatal appointments, they screen for high blood pressure and gestational diabetes; after delivery, they're on the lookout for hemorrhage, infection, and blood clots. But as heart disease rises among the general population, it's affecting more pregnant women, whose hearts must pump one and a half times the normal blood volume. While clinicians have reduced maternal deaths due to hemorrhage and hypertension over the past three decades, deaths due to heart disease have more than doubled.

"This [rise] has been under the radar," said Elliott Main, director of the California Maternal Quality Care Collaborative and the report's lead investigator. "We need to pay much more attention to cardiovascular disease in pregnant women."

The California investigation turned up so many postpartum heart failures that the team sought out a cardiologist who is double certified in high-risk obstetrics to help interpret the data. "We all know maternal mortality is rising," said the specialist, Afshan Hameed, an assistant clinical professor in maternal fetal medicine at University of California, Irvine, then echoed, "But what we've seen more recently is that a substantial number of mothers who recently gave birth are dying from heart disease."

Some are women whose hearts are already compromised, with disease manifesting during pregnancy, Hameed explained. These women might have risk factors like high blood pressure and obesity, and they're more likely to be older and African-American. But about two thirds of the heart-related maternal deaths in California were due to cardiomyopathy, which can develop in women with no risk factors at all. Complicating matters, the signs of heart failure are nearly identical to symptoms common in pregnancy. "Almost all pregnant women are short of breath and fatigued, which are the typical symptoms of heart failure," said Hameed. "Invariably, the women who die are the ones who go undiagnosed for a length of time."

MacDonald was a textbook case. Her hands and feet had been swelling up dramatically during her last trimester, and she'd been waking up late and taking long afternoon naps. "I had shortness of breath and heart palpitations occasionally, and I was extremely fatigued," she said. "I just thought, Wow, this pregnancy is really hard." Since it was her first, she had nothing to compare it to.

On her seventh night in the hospital following an exhausting vaginal delivery of her 9 1/2-pound baby, MacDonald finally paged a nurse and demanded a respiratory consult. She was so desperate for air, she could barely talk—and she was so frustrated that, at one point, she threw a cup of water across the room to get the nurses' attention. "I knew that something was seriously, seriously wrong." From that point, she doesn't remember much beyond being rushed to intensive care. She was in severe congestive heart failure.

MacDonald is what researchers call a "near miss." She was intubated and unconscious for a week while physicians treated her with heart medications. She spent a month in the hospital and faced a daunting recovery at home with her newborn.

One logical response to California's report, or to last year's report by Amnesty International, which announced a "maternal health care crisis" in this country, is to advocate for better access to prenatal care. But California's report suggests that the problem lies in the quality of the care women receive. "Very few women [who died] did not have adequate prenatal care, so we didn't have an issue of access to care. Basically there's universal coverage for pregnant women in California," said Main.

Instead, the report found that delays or inadequacies in diagnoses and treatment were "contributing factors" in a majority—77 percent—of all the deaths. The report also found that race may play a role in treatment: black women were four times more likely to suffer a pregnancy-related death, and there's no clear explanation for the disparity.

Each case can be complicated. "You can't typically point to one single mistake," says Morton. "A maternal death is like a shuttle disaster. There are multiple points of failure at multiple points in time throughout multiple places in the system." A contributing factor for women with heart disease is often failure to diagnose—but on the flipside, women who are diagnosed may be at a higher risk for surgery, which can also be a contributing factor.

"A lot of times what happens is that if a woman has a diagnosis of cardiac disease of any kind, obstetricians tend to think that a cesarean delivery is the better choice," says Hameed. The prevailing wisdom is that avoiding labor puts less of a strain on the heart. "But that is not in fact true, because cesareans have more complications in general," Hameed explained. Fifteen percent of deaths in California were directly related to cesarean sections. "Except for a selected few cases, women with heart disease are better off delivering vaginally."

As for whether other obstetric interventions, such as labor induction or epidural, can exacerbate heart conditions, investigators say they need more data to know.

Angela Armen, also a fit 31-year-old with no risk factors, was lucky. When she showed up at a Scottsdale, Ariz., emergency room gasping for breath in 2007, four weeks after giving birth to her third child, staff sent her home with a referral to a cardiologist "just in case," whom she waited a full month to see. Armen eventually got treatment and recovered. Many clinicians, it seems, are distracted by a woman's pregnancy—they attribute all unusual physical symptoms to it, even when they're signs of a serious condition.

"The take-home message is that if any woman during or after pregnancy is complaining of shortness of breath, heart palpitations, tiredness, or swelling, she needs to be evaluated as if she were otherwise not pregnant," said Hameed. "Just like a man."